1994 Fiscal Year Final Research Report Summary
Carbonate deposition/dissolution and environmental changes through the earth histroy
| Project/Area Number |
05303001
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Geology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MATSUMOTO Ryo The University of Tokyo Graduate School of Science Professor, 大学院・理学系研究科, 教授 (40011762)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Satoshi Ryukyu University Faculty of Science Lecturer, 理学部, 講師 (50124855)
ICHIKUNI Masami Saitama University Faculty of Engineering Professor, 工学部, 教授 (20005804)
AIZAWA Shoichi Gunnma University Faculty of Engineering Assistant, 工学部, 助手 (20008527)
NAKAMORI Tooru Tohoku University Faculty of Science Associate Professor, 理学部, 助教授 (00192229)
FUJIMAKI Hirokazu Tohoku University Faculty of Science Professor, 理学部, 教授 (90133933)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Carbonate rocks / Isotopic compositions / Sea level changes / Chemical weathering / Coral reef / Strontiumu isotopes |
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| Research Abstract |
1.Research Activities
Number of research meetings and seminars were held to stimulate discussions and exchange of information. Paperd read at these meetings have been published as an annual report or abstract volums. We also established a data-base for carbonate study(CADBA), which includes approximately 180,000 articles.
2.Highlights of the Project
We revealed that the carbon isotopic composition of carbonates shows strong netagive anomly just below the Precambrian/Cambrian boundary, and strong positive anomaly just above the boundary. This implies that the shallow sea water was enriched in organic carbon derived carbonate species just before the boundary. Based on the strontiumu isotope stratigraphy, dolomitization of the Miocene reefal limestonewas found to have been occurred by the mixing of sea-water and meteoric waters during the period of low sea levels.
We have suggested the possibility that ooids might have been formed under strong influence of bacterial activity(bacterial induced carbonates), based on the electron microscope observations.
3.Impact of the project
Several cooperative research projects have been initiated and stimulated through the descussion and cooperation at the meetings. This project has made clearl that the elucidation of a vital effects in biomineralization and disequibrium precipitation of inorganic carbonates are crucial for the fuller understanding of carbonate precipitation and dissolution.
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